Question

打字稿类型别名可以支持默认参数吗？例如：

export type SomeType = {
    typename: string;
    strength: number;
    radius: number;
    some_func: Function;
    some_other_stat: number = 8; // <-- This doesn't work
}

错误是A type literal property cannot have an initializer.

我找不到与此关键字相关的文档-type关键字在其他所有也称为type的后面都非常模糊。我可以做些什么来使打字稿中的type具有默认参数值？

Answer 1

不能将默认值直接添加到类型声明中。

您可以改为执行以下操作：

20-05-18 09:27:18.629  WARN 24876 --- [io-8443-exec-10] o.a.c.j.i.WebApplicationExceptionMapper  : javax.ws.rs.InternalServerErrorException: HTTP 500 Internal Server Error
at org.apache.cxf.jaxrs.utils.SpecExceptions.toInternalServerErrorException(SpecExceptions.java:79)
at org.apache.cxf.jaxrs.utils.ExceptionUtils.toInternalServerErrorException(ExceptionUtils.java:113)
at org.apache.cxf.jaxrs.interceptor.JAXRSInInterceptor.convertExceptionToResponseIfPossible(JAXRSInInterceptor.java:227)
at org.apache.cxf.jaxrs.interceptor.JAXRSInInterceptor.processRequest(JAXRSInInterceptor.java:215)
at org.apache.cxf.jaxrs.interceptor.JAXRSInInterceptor.handleMessage(JAXRSInInterceptor.java:77)
at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308)
at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:262)
at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:208)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:160)
at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:180)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:299)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doGet(AbstractHTTPServlet.java:223)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:274)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.EOFException: No content to map to Object due to end of input
  at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
  at org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:2691)
  at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1315)
  at org.codehaus.jackson.jaxrs.JacksonJsonProvider.readFrom(JacksonJsonProvider.java:419)
  at org.apache.cxf.jaxrs.utils.JAXRSUtils.readFromMessageBodyReader(JAXRSUtils.java:1348)
  at org.apache.cxf.jaxrs.utils.JAXRSUtils.readFromMessageBody(JAXRSUtils.java:1299)
  at org.apache.cxf.jaxrs.utils.JAXRSUtils.processParameter(JAXRSUtils.java:825)
  at org.apache.cxf.jaxrs.utils.JAXRSUtils.processParameters(JAXRSUtils.java:789)

Answer 2

类型在运行时中不存在，因此默认值没有意义。如果要使用默认默认值，则必须使用运行时中存在的内容，例如类或工厂函数

打字稿类型别名的默认值

2 个答案: